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crashing my application due to NSAUTORELEASENOPOOL

Answer 1

+3 A:

You are missing an instance of NSAutoreleasePool, probably because your method is executed on another thread.

Simply create it, and release it at the end of your method:

NSAutoreleasePool * pool = [ [ NSAutoreleasePool alloc ] init ];
/* your code... */
[ pool release ];

NSAutoreleasePool are responsible to release the objects on which the 'autorelease' message is send.
Note that when using convenience constructors, objects are autoreleased. So if you have no pool, the objects won't be released.

A pool exists on the main thread, but for methods executing on other threads, it needs to be created manually.

Note that you can have more than one instance of NSAutoreleasePool in the same thread. It's sometimes useful to avoid long retain cycles.

Macmade 2010-07-20 14:59:55

thanks iwilll go through this

lak in iphone 2010-07-20 15:06:54

Answer 2

+1 A:

You crash because you auto-release some objects, with no auto-release pool in place.
An auto-release pool is an object that holds the objects that are sent an autorelease message, and take care of releasing them when it receive the drain message.
Cocoa expects to always have an autorelease pool available.

Why you have no auto-release pool is hard to say without more context.

When your app start, in main.m, an auto-release pool is created. Maybe you modified this code?
Or you created a new thread, but didn't created an auto-release pool.

Anyway, here is how to create one:

NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init];
// Your code goes here
[pool release];

Guillaume 2010-07-20 15:07:49

Answer 3

+1 A:

Your first issue is, like the other community members here already mentioned, that you are running a thread without an NSAutoreleasePool allocated or "wrapping it". But the main issue i believe you have is, that you try to draw something on the screen from another Thread than the one the User Interface was allocated.

Never call any messages that manipulate some UI elements from a different Thread. The reason is that Graphic Buffer and other appropriate memory is not threadsafe. Doing so leads to undefined behavior, an assertion failure or just crashes. When you need to update any UI Elements from another Thread put your messages in the appropriate runloop by calling

[objectToUpdate performSelectorOnMainThread:withObject:waitUntilDone:]

or with whatever synchronizing mechanism you use. The above message puts the message in the queue of the runloop of the main thread. It will be executed when the runloop continues next time, but in the correct thread. The precondition is, for sure, that you initialized your UI Elements in the main tread (which is the case in 99% of all applications). Otherwise you could call the

[objectToUpdate performSelector:onThread:withObject:waitUntilDone:]

message to address any other thread.

thatsdisgusting 2010-07-20 15:28:47

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crashing my application due to NSAUTORELEASENOPOOL

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